1. Technical Field
The invention relates to methods and materials for evaluating rheumatoid arthritis as well as for determining an individual""s predisposition to have severe rheumatoid arthritis disease.
2. Background Information
Rheumatoid arthritis (RA) affects individuals in the prime of their life and is feared because of its potential to cause chronic pain and irreversible damage of tendons, ligaments, joints, and bones. The symmetrical involvement of small peripheral joints has an enormous impact on hand and foot functions and poses therapeutic challenges that cannot be easily overcome by joint replacement. Also, systemic manifestations of RA are not rare and can range from relatively minor problems, such as rheumatoid nodules, to life-threatening organ disease.
In addition, RA is a systemic inflammatory disease that primarily manifests itself as synovial inflammation of diarthrodial joints. The typical histopathological changes include dense infiltration of the synovial membrane by mononuclear cells, neoangiogenesis, and hypertrophy and hyperplasia of the synovial lining (Harris E D (ed); Rheumatoid Arthritis, Philadelphia, WB Saunders Co., pp.3-212 (1997); and Hale L P, Haynes B F: Pathology of rheumatoid arthritis and associated disorders. Arthritis and Allied Conditions. A textbook of Rheumatology. Edited by Koopman W J. Baltimore, Williams and Wilkins, pp.993-1016 (1997)). The etiopathogenesis of the syndrome is not understood. Several lines of evidence support a central role of T lymphocytes in the disease-specific pathogenic events (Todd, et al. Science, 240:1003-1009 (1988); Panayi, et al., Arthritis Rheum, 35:729-735 (1992); and Goronzy J J, Weyand C M: Rheum Dis Clin North Am, 21:655-674 (1995)). An alternative hypothesis, namely, that macrophages are the pivotal cell type in rheumatoid synovitis, has also been proposed (Firestein G S, Zvaifler N J: Arthritis Rheum 33:768-773 (1990); and Burmester, et al., Arthritis Rheum, 40:5-18 (1997)). Whether only T cells or only macrophages or both are the causative elements in RA remains a matter of controversy (Feldmann, et al., Cell, 85:307-310 (1996); and Fox, Arthritis Rheum 40:598-609 (1997)).
RA is primarily a clinical diagnosis. Symmetrical joint involvement, dominant manifestations in peripheral joints, rheumatoid factor production, and the formation of rheumatoid nodules are considered when the diagnosis is made (Arnett, et al., Arthritis Rheum. 31:315-324 (1988)). The histological appearance of the synovium varies quite extensively and the pathological findings are usually not helpful in distinguishing RA from other inflammatory arthropathies (Hale L P, Haynes B F: Pathology of rheumatoid arthritis and associated disorders. Arthritis and Allied Conditions. A textbook of Rheumatology. Edited by Koopman W J. Baltimore, Williams and Wilkins, pp.993-1016 (1997)). In addition, no information is available on the mechanisms underlying the topographical arrangement of the inflammatory infiltrate in the rheumatoid synovium.
Therapeutic management of RA has steadily improved over the last decades, mostly due to the recognition that destruction caused by chronic inflammation is irreversible and that only early and aggressive intervention can enhance therapeutic benefit. Consequently, RA patients are now being treated early in the disease course and disease modifying agents are widely used. Despite these successes, major challenges remain. Presently, no curative intervention is available, side effects of therapies are significant, and the disease may still progress while the patient is being treated.
The invention involves methods and materials for evaluating rheumatoid arthritis in a patient. Specifically, the invention provides methods and materials for classifying a rheumatoid arthritis condition as diffuse, follicular, or granulomatous. In addition, the invention provides methods and materials for determining if an individual suffering from a rheumatoid arthritis condition will develop severe disease. Useful indicators for severe disease include, without limitation, subcutaneous nodule formation (nodularity) and extra-articular involvement.
The invention is based on the discovery that the level of particular cytokines within tissue or the histological appearance of tissue or both can be used to classify a rheumatoid arthritis condition as diffuse, follicular, or granulomatous. This classification is important since granulomatous patients are more susceptible to severe rheumatoid arthritis disease. Severe rheumatoid arthritis disease can involve, without limitation, major organ involvement, which can be life threatening, and major joint destruction, which can be crippling. Thus, proper classification of a granulomatous rheumatoid arthritis condition can help provide clinicians and patients with information that can be used to determine adequate treatments.
Specifically, the invention involves analyzing a synovial tissue biopsy for particular cytokines such as IL-4, IL-10, and IFN-xcex3, or for particular histological characteristics, or both. For example, a patient can be classified as having a diffuse condition when tissue from that patient contains low levels of IL-4, IL-10, and IFN-xcex3, or as having a follicular condition when tissue from that patient contains high levels of IL-10 and IFN-xcex3 and low levels of IL-4. A particular level of a particular cytokine can be determined to be high or low based on the levels measured from various populations. Such populations can include, without limitation, populations of patents with a diffuse condition, follicular condition, or granulomatous condition, patients with subcutaneous nodule formation, patients with extra-articular involvement, patients with major joint destruction, and healthy individuals.
The invention also is based on the discovery that patients presenting similar rheumatoid arthritis symptoms can have different levels of particular cytokines within their tissue or different histological appearance of their tissue. Thus, determining the tissue cytokine profile or the histological characteristics of a synovial tissue sample from a patient can be used to determine the proper treatment protocol. For example, two patients having similar rheumatoid arthritis symptoms may have different levels of IL-10 within their tissue. The patient with low levels may benefit from a treatment of IL-I 0 while the patient with high levels of IL-10 may benefit from treatment with IL-10 inhibitors such as anti-IL-10 antibodies. Thus, determining the tissue cytokine profile or the histological characteristics of a tissue sample from a patient can help provide clinicians and patients with information that can be used to determine adequate treatments.
In addition, the invention is based on the discovery that the predisposition to develop severe disease can be determined in patients classified as having diffuse or follicular disease by analyzing the patient""s HLA-DRB1 alleles or frequency of CD4+/CD28null cells or both. Determining a patient""s predisposition to develop severe disease is important since it allows clinicians and patients to plan and treat accordingly. Again, severe rheumatoid arthritis disease can involve, without limitation, extra-articular involvement and major joint destruction. Moreover, analyzing a patient""s HLA-DRB1 alleles and/or frequency of CD4+/CD28null cells can be used to determine whether a patient classified as having diffuse or follicular disease with a propensity for severe disease will have major organ damage, major joint destruction, or both.
Specifically, the invention involves determining whether a patient having a diffuse or follicular condition has zero, one, or two HLA-DRB1 alleles that are associated with RA and/or whether that patient has an elevated frequency of CD4+/CD28null cells. For example, HLA-DRB1 alleles that are associated with RA can be any allele having a polymorphism associated with rheumatoid arthritis including HLA-DRB1 alleles that encode polypeptides having an uncharged amino acid at position 74, no negatively charged amino acid at position 70, and a positively charged amino acid at position 71. Patients having RA-associated polymorphisms for one or both HLA-DRB1 alleles or having an elevated frequency of CD4+/CD28null cells can be classified as having the potential to form severe disease.
In general, the invention features a method for diagnosing a rheumatoid arthritis condition in a patient. The method includes determining the level of a cytokine (e.g., IL-4, IL-10, and IFN-xcex3) within a sample from the patient, comparing the level of the cytokine to a reference level to obtain information about the rheumatoid arthritis condition, and classifying the rheumatoid arthritis condition as a diffuse, follicular, or granulomatous condition based on the information. The sample can be a tissue biopsy (e.g., a synovial tissue biopsy). The reference level can be the median level of the cytokine found in tissue samples derived from a population. The population can include a population of patients having a diffuse rheumatoid arthritis condition, a population of patients having a follicular rheumatoid arthritis condition, a population of patients having a granulomatous rheumatoid arthritis condition, a population of healthy individuals, a population of patients having subcutaneous nodules, a population of patients having extra-articular involvement, or a population of patients having major joint destruction.
In another embodiment, the invention features a method for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The method includes determining the level of a cytokine (e.g., IL-4, IL-10, and IFN-xcex3) within a sample from the patient, determining the frequency of CD4+/CD28null cells in the patient, comparing the level of the cytokine to a reference level and the frequency of CD4+/CD28null cells to a reference frequency to obtain information about the predisposition, and determining if the patient is predisposed to develop severe disease based on the information. The sample can be a tissue biopsy (e.g., a synovial tissue biopsy). The reference level can be the median level of a the cytokine found in tissue samples derived from a population. The population can include a population of patients having a diffuse rheumatoid arthritis condition, a population of patients having a follicular rheumatoid arthritis condition, a population of patients having a granulomatous rheumatoid arthritis condition, a population of healthy individuals, a population of patients having subcutaneous nodules, a population of patients having extra-articular involvement, or a population of patients having major joint destruction. The frequency of CD4+/CD28null cells can be the percent of CD4+ cells that are CD28 negative. In addition, the reference frequency can be derived from the CD4+/CD28null cell frequency from a population.
Another embodiment of the invention features a method for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The method includes determining the level of a cytokine (e.g., IL-4, IL-10, and IFN-xcex3) within a sample from the patient, comparing the level of the cytokine to a reference level to obtain information about the rheumatoid arthritis condition, determining the presence of a polymorphism in an HLA-DRB1 allele in the patient, and determining if the patient is predisposed to develop severe disease based on the information and the presence of the polymorphism. The sample can be a tissue biopsy (e.g., a synovial tissue biopsy). The reference level can be the median level of the cytokine found in tissue samples derived from a population. The population can include a population of patients having a diffuse rheumatoid arthritis condition, a population of patients having a follicular rheumatoid arthritis condition, a population of patients having a granulomatous rheumatoid arthritis condition, a population of healthy individuals, a population of patients having subcutaneous nodules, a population of patients having extra-articular involvement, or a population of patients having major joint destruction. The polymorphism can include an HLA-DRB1 allele that encodes a polypeptide having an uncharged amino acid at position 74, or an HLA-DRB1 allele that encodes a polypeptide free from negatively charged amino acids at positions 70 and 71.
Another embodiment of the invention features a method for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The method includes determining the level of a cytokine within a sample from the patient, determining the frequency of CD4+/CD28null cells in the patient, comparing the level of the cytokine to a reference level and the frequency of CD4+/CD28null cells to a reference frequency to obtain information about the rheumatoid arthritis condition, determining the presence of a polymorphism in an HLA-DRB1 allele in the patient, and determining if the patient is predisposed to develop severe disease based on the information and the presence of the polymorphism.
In another aspect, the invention features a kit for providing diagnostic information about a rheumatoid arthritis condition in a patient. The kit contains a binding pair member and a reference chart. The binding pair member has specific binding affinity for a cytokine such that the level of the cytokine within a sample from the patient is determinable, and the reference chart contains information about cytokine levels such that an indication of the diffuse, follicular, or granulomatous nature of the rheumatoid arthritis condition is determinable based on the level of the cytokine within the sample.
In another embodiment, the invention features a kit for providing diagnostic information about a rheumatoid arthritis condition in a patient. The kit contains a binding pair member and a reference chart. The binding pair member has specific binding affinity for a nucleic acid sequence encoding a cytokine such that the level of the cytokine within a sample from the patient is determinable, and the reference chart contains information about cytokine levels such that an indication of the diffuse, follicular, or granulomatous nature of the rheumatoid arthritis condition is determinable based on the level of the cytokine within the sample.
In another embodiment, the invention features a kit for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The kit contains a first binding pair member, a second binding pair member, and a reference chart. The first binding pair member has specific binding affinity for a cytokine or nucleic acid encoding the cytokine such that the level of the cytokine within a sample from the patient is determinable. The second binding pair member has specific binding affinity for a CD4+/CD28null cell marker such that the frequency of CD4+/CD28null cells in the patient is determinable. The reference chart contains information about cytokine levels and CD4+/CD28null cell frequencies such that an indication of the predisposition is determinable based on the level of the cytokine within the sample and the frequency of CD4+/CD28null cells in the patient.
In another embodiment, the invention features a kit for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The kit contains a binding pair member, an oligonucleotide primer, and a reference chart. The binding pair member has specific binding affinity for a cytokine or nucleic acid encoding the cytokine such that the level of the cytokine within a sample from the patient is determinable. The oligonucleotide primer has specific binding affinity for at least a portion of the locus containing an HLA-DRB1 allele such that a polymorphism of HLA-DRB1 allele in the patient is determinable. The reference chart contains information about cytokine levels such that an indication of the predisposition is determinable based on the level of the cytokine within the sample and the polymorphism of the patient. The kit can contain a plurality of the oligonucleotide primers.
In another embodiment, the invention features a kit for determining the predisposition of a rheumatoid arthritis patient to develop severe disease. The kit contains a first binding pair member, a second binding pair member, an oligonucleotide primer, and a reference chart. The first binding pair member has specific binding affinity for a cytokine or nucleic acid encoding the cytokine such that the level of the cytokine within a sample from the patient is determinable. The second binding pair member has specific binding affinity for a CD4+/CD28null cell marker such that the frequency of CD4+/CD28null cells in the patient is determinable. The oligonucleotide primer has specific binding affinity for at least a portion of the locus containing an HLA-DRB1 allele such that the a polymorphism of the HLA-DRB1 allele in the patient is determinable. The reference chart contains information about cytokine levels and CD4+/CD28null cell frequencies such that an indication of the predisposition is determinable based on the level of the cytokine within the sample, the frequency of CD4+/CD28null cells in the patient, and the polymorphism of the HLA-DRB1 allele.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.